Charge forming device



Feb. 13, 1934. F. E. ASELTINE CHARGE FORMING DEVICE Filed May 23, 1930 2Sheets-Sheet l Feb. 13, 1934. F. E. ASELTINE 1,946,603

CHARGE FORMING DEVICE Filed May 23, 1930 2 Sheets-Sheet 2 a 35 /zo l/ #8Z 74 78 80 3 3e /5a 72' 4 mm .24

as A 5 A? I nil/4o jar 28 54 I56 /42 ggg 44 I52 A32 2 L36: 4- us a 30I30 i I 20 1 I 72 log H I 4.: I

a 3mm die/lbw c9? 3 J ns 5L4 l atented Feb. 13, 1934 PATENT OFFICECHARGE FORMING DEVICE Fred E. Aseltine, Dayton, Ohio, assignor to DelcoProducts Corporation, Dayton, ()hio, a corporation of DelawareApplication May 23, 1930. Serial No. 454,912

18 Claims.

This invention relates to charge forming devices for internal combustionengines, and more particularly to devices of this character whichcomprise a plurality of primary carburetors, each of which delivers aprimary mixture of air and fuel to one of a plurality of secondarymixing chambers located adjacent the engine intake ports and in whichthe primary mixture is mixed with additional air under certain operatingconditions.

Devices of this character are disclosed in the copending applications ofWilford I-l. Teeter and Fred E. Aseltine, Serial No. 221,371, filedSeptember 22, 1927, and Wilford H. Teeter, Serial No. 221,372, filedSeptember 22, 1927.

It is the object of the present invention to provide in a device of thischaracter means for improving the proportions of the mixture duringoperation under all operating conditions, and particularly for enrichingthe mixture during the acceleration period and for delivering theenriched mixture to the cylinders substantially simultaneously with theopening of the throttle. With this object in view, one feature of theinvention consists in the provision-of primary mixture passages whichare supplied with air directly from the atmosphere instead of from themain air chamber, as in the earlier devices.

A further feature of the invention consists in the provision of apositively controlled needle valve for regulating the supply of fuel tothe fuel jets during all operating conditions.

A still further feature of the invention consists in the provision of acam for operating the above mentioned fuel valve which is adjustable onthe throttle shaft so that by adjustment of such cam, the position ofthe fuel valve at idling can be readily accomplished.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred embodiment of one form of the presentinvention is clearly shown.

In the drawings:

Fig. 1 is a plan view of a charge forming device constructed inaccordance with the present invention.

Fig. 5 is a fragmentary, left side elevation of the device with partsbroken away and other parts shown in section.

Fig. 6 is a right side elevation of the device showing the throttleoperating mechanism.

The device disclosed comprises a main air manifold 10 having threeoutlet branches 12, 13 and 14. Each of these branches communicates withone of the intake ports 15 of a multicylinder engine and each isprovided with an attaching U6 flange 16 for securing it to the engineblock in the usual manner. Adjacent its inlet, the manifold is providedwith a flange 18 to which the carburetor unit is adapted to be secured.

The carburetor unit comprises a main housing 20, having an attachingflange 22, adapted to be secured to the flange 18 by screws 24. An airinlet coupling 26 is positioned in an opening in the upper wall of themain housing and admits air thereto, while a casting 28 which isprovided for a purpose hereinafter described, is secured to the bottomof the main housing 20. A sheet metal fuel bowl 30 is held tight againsta shoulder 32 formed on the casting 28 and fuel, which is conducted to abowl from a main source of supply, is controlled by a float 34, whichoperates in the usual manner to maintain a substantially constant levelof fuel in the bowl.

A plurality of primary mixture passages 36 are provided in'the lowerwall of the main housing, the construction of these passages being morefully described hereinafter. Fuel is supplied to each of these passagesby a plurality of fuel jets 38 and 40, the jet 38 functioning under alloperating conditions and the jet 40 operating only at to relatively highspeeds for reasons which will be more fully set forth later. Fuel isconducted to all of the fuel jets through a vertical passage 42,depending from a distributor block 44, secured by screws or in any otherdesirable way to the bottom of the main housing. The passage 42, at itslower end, communicates with a horizontal passage 46, which communicatesin turn with a vertical passage 48 extending upwardly from the passage42, all of the fuel passages being formed 16) in a single integralmember. The fuel is admitted to the vertical passage 48 through anorifice 60 and the passage 48 is restricted at 62.,

a fuel valve 64 being received in the passage 48 and projecting into therestriction 62 to control the flow of fuel thereto. This valve extendsupwardly through the top of the fuel bowl and is controlled by theprimary throttle in a manner to be described more fully hereinafter. Thevertical passage 42 connects at its upper end with horizontal fuel canal66, which, through the orifices 68, supplies fuel to a channel 70,formed in the lower wall of the main housing and which communicates withall of the jets 38 and 40 in all of the primary mixture passages tosupply fuel thereto.

According to the present invention, the mixture passages 36 are somewhatsmaller than in the applications above referred to and instead of beingsupplied with air which is admitted through the coupling 26 in a mannerhereinafter described,v

communicate directly with the atmosphere, each of said passages beingprovided with an air inlet bushing 72, which admits air thereto. Each ofthe primary mixture passages 36 is slightly enlarged at its anteriorend, as indicated at 74 and a small Venturi tube '76 is positioned ineach mixture passage within such enlargement, ribs 78 being formed onthe Venturi tubes which fit relatively tightly within the enlargements74 and when the Venturi tubes are in position they are held closelyagainst shoulders 80 at the inner end of each enlargement 74 by means ofthe bushings '72, which are threaded in the wall of the housing andwhich may be screwed inwardly against one of the ribs 78 on each tube.The fuel jets 38, each supply fuel to an annular channel 82, formed inthe wall of the main housing 20 and communicating with the space betweenthe above mentioned shoulders 78, while each of the Venturi tubes isprovided with a series of orifices 84, which connect the channels 82with the interior of the Venturi tubes and supply fuel thereto from'thejets 38.

The inner ends of the Venturi tubes are reduced in size as indicated at86, and these re- .duced ends are slightly spaced from the walls of theprimary mixture passages to provide a space 88 between the wall of eachmixture passage and the Venturi tube therein. The high speed fuel jets40, each communicate with a short passage 90 in the wall of the housing,which in turn com- .municates with one of the spaces 88, abovereferred-to. Since the fuel feeding orifices 84. admit fuel to theinterior of the Venturi tube at substantially the point of greatestsuction therein, while the high speed fuel jets supply fuel to a spacebetween the inner end of the Venturi tube and the well of the mixturepassage which is protected from the aspirating action of the incomingair, it will be obvious that the high speed fuel jets are ineffective tosupply fuel to the mixture passages until after a predetermined speedhas been reached while the fuel inlets 84 will supply fuel to theVenturi tubes under all oper ating conditions. Means is provided forequalizing the'pressure in the three primary mixture pasages comprisinga horizontal passage 85, bored in the wall of the main housing and threeshort vertical passages 87 extending downward from said horizontalpassage, one of said passages 8'? connecting with each of the primarymixture passages 36. I

A single throttle valve 92 which extends across all of the mixturepassages, is provided with grooves 94- which register with said passagesand control the flow therethrough. This throttle is journalled in thehousing 20 and is operated by means disclosed more fully herein. Theprimary mixture passages 36, when the device is assembled, are adaptedto register withconduits which convey the primary mixture to secondarymixing chambers in the outlet branches of the manifold as fullydisclosed-in copending application Serial No. 221,371. One of theseconduits, which is in form of a tube 96, is fixed in the wall of theoutlet branch 12 and conveys primary mixture to the secondary mixingchamber formed in that particular manifold branch, as shown in Fig. 1.

As stated above, the valve 64 which is received in the fuel passage 48,extends upwardly through the top of the fuel bowl, being held in itsuppermost position by means of a spring 98 received between the upperend of the conduit 48 and a collar 100 secured to the valve stem. Thisvalve is normally held in its lowermost position when the throttle isclosed by means of a cam 102 adjustably secured on the end of a spindle104 projecting from the primary throttle by means of a set screw 106 orother suitable means. The cam permits the spring 98 to lift the valveprogressively as the throttle is moved toward open position to enlargethe fuel passage through the restriction 62, thus controlling the areaof the fuel passage in accordance with the position of the primarythrottle. It will be obvious that by adjustment of the cam on itsspindle through the medium of the set screw, the position occupied bythe valve when the throttle is in its closed or idling position can bevaried to suit different requirements of the engine.

Air is admitted to the carburetor through the coupling 26 and iscontrolled by a valve 108 normally held against the seat 110 by a spring112, secured between the valve and a flange 114 projecting from a sleeve116, slidable on a sleeve 118, fixed in the main housing and guiding thestem 120 to the upper end of which the valve 108 is secured. In order toaid in starting the engine, the sleeve 116 is adapted to be lifted intoengagement with the valve 108 by means not disclosed herein, to holdsaid valve closed. According to the present invention, air for carryingthe starting fuel to the cylinders is supplied through the Venturi tubeshereinbefore described. The choke choke mechanism constitutes no part ofthe present invention and is fully disclosed in application Serial No.221,371.

The valve 108 admits air to a main air chamber 122 which, according tothe present invention, has no means of communication with the primarymixture passages as in the earlier forms of this device, but is adaptedto supply air to the secondary mixing chambers through a secondary airpassage 124, this passage being controlled by a manually operablethrottle valve 126, secured to a shaft 128, journalled in the main.housing. The valve 126 is operated simultaneously with the primarythrottle, the latter being provided with an operating arm 127, which issecured in any desirable manner to a spindle 129, projecting from oneend of the throttle, and adapted to be connected to some form ofoperating-means extending to a point convenient to the operator of thevehicle. A link 131, which is pivotally connected with the arm 127 isalso pivotally connected at its upper end withan arm 135, secured to oneend of the shaft 128 in .any desirable way. It should be clear thatthere is no lost motion connection between the primary throttle and thevalve 126, in this device as in the devices shown in the earlierapplications above referred to. All movements of the throttle produce acorresponding movement of the valve 126. A hole 137 is provided in eachvalve to admit air during idling;

To prevent fluttering of the air valve and to retard its openingmovement temporarily, following an opening movement of the throttle, toenrich the mixture during the acceleration period, a. dashpot isprovidedincluding a cylinder III 130 supported in a fixed sleeve 132,whichlis part of the casting 28. Slidable within the cylinder 130 is apiston 134, secured to the inner end of the valve stem 120 in the marmerdisclosed in the above mentioned earlier applications. Port 136 isprovided in the wall of the cylinder which '00- operates with a port 138in the sleeve 132 to permit fuel to enter the cylinder. It will beobvious that on opening movement of the valve, the above mentionedcylinder and piston will retard its movement temporarily restricting theadmission of air to the secondary mixing chambers and thus enriching themixture temporarily to provide a mixture of the proper proportions toproduce smooth acceleration.

The cylinder 130 isslidable within the sleeve 132 and is adapted to belifted on opening movements of the throttle by a bifurcated arm 140,which has pins projecting therefrom and engaging in the groove 142formed in the top of the cylinder. In order to simplify the disclosure,the operating means for this arm has not been shown herein since it isfully shown in the earlier applications. It is sufficient for thepurposes of this disclosure to state that a shaft 144 to which this armis secured, is adapted to be rocked on opening movements of the throttleso as to move the arm in a clockwise direction and lift the cylinder,thus increasing the retarding effect of the dashpot and aiding in theenriching of the mixture.

The secondary mixing chambers are in the form of Venturi tubes ofidentical construction, one of these tubes being indicated by thereference numeral 150 and shown in Fig. 2. Each of the Venturi tubes isprovided with an external rib 152, which is adapted when the device isassembled, to be clamped between shoulders 154 and 156 on the manifoldand engine block respectively. The tubes are so positioned that thepoint of greatest suction therein is approximately at the end of theprimary fuel delivery conduits so as to accelerate the flowtherethrough.

The operation of this device is substantially as follows. In the earlierapplications above re ferred to, some difficulties have sometimes beenobserved on acceleration due to the fact that after the secondary airpassage is opened, the air which is admitted following any openingmovement of the throttle, beingmuch lighter than the rich primarymixture, reaches the secondary mixing chambers before the enrichedprimary mixture reaches such chambers. By means of the device disclosedherein, the velocity of flow of the primary mixture through *which isadmitted to the primary mixture conduits is supplied directly from theatmosphere, the pressure differential is' much greater than in earlierdesigns and also much greater than between the ends of the secondary airpassage. Therefore, the speed at which the primary mixture travelsthrough such conduits is very greatly increased so that notwithstandingthe greater. weight of the primary mixture and the effect of inertia duethereto, such primary mixture will reach the secondary mixing chamberssubstantially as soon as the air admitted through the main air inlet.

. Further, the supply of fuel to the primary mixture passages can'bemore accurately controlled when the supply is regulated at all speeds bya valve controlled by a cam, the ,design of which can be varied to suitthe conditions which are met in any particular engine than where thefuel is controlled in part by a fixed meteringorifice and duringotheroperating conditions isalso controlled by a fuel valve which isbrought into action'at some predetermined speed. In earlier chargeforming devices of this general type a fuel valve was employed which wasdesigned -to be opened approximately at the same time the auxiliary airpassage was opened but unless the parts were accurately synchronized sothat the opening of the fuel valve would begin at exactly the correcttime, the mixture was inaccurate, and. it was found to be very difficultto keep the parts operating in exact synchronization, particularly inevent of the parts becoming worn. In this device, however, the valvebegins to open immediately .as the primary throt tle and the secondarythrottle are opened and is opened continuously as they are opened sothat the above difliculties are largely avoided.

While the form of embodiment of the present invention as hereindisclosed, constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow.

What is claimed is as follows:

1. A charge forming device for internal combustion engines having aplurality of intake ports, comprising a main air manifold having outletbranches communicating with said intake ports, a plurality of primarycarburetors each of which is adapted to supply a superrich mixture toone of said branches under all operating conditions, throttling meanscontrolling the flow from the primary carburetors and a single secondarythrottle for controlling the flow through a plurality of the outletbranches of said manifold.

2. A charge forming device for internal combustion engines having aplurality of intake ports, comprising a -main air manifold having outletbranches communicating with said intake ports, a plurality of primarycarburetors each of which is adapted to supply a super-rich mixture toone of said branches under all operat-' ing conditions, throttling meanscontrolling the fiow from the primary carburetors and a single secondarythrottle for controlling the flow through all of the outlet branches ofsaid manifold.

3. A charge forming device for internal combustion engines having aplurality of intake ports, comprising a main air manifold having 185outlet branches communicating with said intake ports, a plurality ofprimary carburetors each of which is adapted to supply a super-richmixture .to one of said branches under all operating conditions,throttling means controlling the flow from the primary carburetors anair bustion engines having a plurality of intake each of which isadapted to supply a super-rich mixture to one of said branches under alloperating conditions, throttling means controlling the flow from theprimary carburetors a single secondary throttle for controlling the flowthrough the outlet branches of the manifold, and means for admitting airdirect from atmosphere to the primary carburetors.

5. A charge forming device for internal combustion engines having incombination a plurality of secondary mixing chambers, a plurality ,ofprimary carburetors for supplying a. superrich primary mixture of airand fuel to said secondary mixing chambers under all operatingconditions, an air passage supplying air to all of said secondary mixingchambers, a single primary throttle controlling said primarycarburetors, a single secondary throttle regulating flow through saidair passage, and means for operating the two throttles simultaneously.

6. A charge forming device for internal combustion engines having incombination a plurality of secondary mixing chambers, a plurality ofprimary carburetors for supplying a primary mixture of, air and fuel tosaid secondary mixing chambers under all operating conditions, a singleprimary throttle controlling said primary carburetors, a singlesecondary throttle regulating flow through said secondary mixingchambers, and means for operating the two throttles simultaneouslythroughout the entire movement of said throttle.

'7. A charge forming device for internal combustion engines having incombination a plurality of secondary mixing chambers, a plurality ofprimary carburetors for supplying a super-rich primary mixture of airand fuel to said secondary mixing chambers under all operatingconditions, a single primary throttle controlling said primarycarburetors, a single secondary throttle regulating flow through saidsecondary mixing chambers, and means for operating the two throttlessimultaneously throughout the entire movement of said throttles.

8. A charge forming device for internal combustion engines having incombination a plurality of secondary mixing chambers, a plurality ofprimary carburetors for supplying a superrich primary mixture of air andfuel to said secondary mixing chambers under all operating conditions,an air passage supplying air to all of said secondary mixing chambers, asingle primary throttle controlling said primary carburetors, a singlesecondary throttle regulating flow through said air passage, and acommon operating means for the two throttles.

9. A charge forming device for internal combustion engines having incombination a plurality of secondary mixing chambers, a plurality ofprimary carburetors for supplying a superrich primary mixture of air andfuel to said secondary mixing chambers under all operating conditions, asingle primary throttle controlling said primary carburetors, and asingle secondary throttle for regulating the flow through the secondarymixing chambers, and common operating means for the two throttles.

10. A charge forming device for internal combustion engines having incombination a plurality of secondary mixing chambers, a plurality ofprimary carburetors adapted to supply a super-rich mixture of fuel andair to said secondary mixing chambers, a primary throttle controllingfiow through said primary carburetors, a secondary throttle controllingthe fiow of air to said secondary mixing chambers, and means Iassociated with secondary throttle to permit the flow of a limitedamount of air to said secondary mixing chambers during the idling of theengine.

11. A charge forming device for internal combustion engines having incombination a plurality of secondary mixing chambers, a plurality ofprimary carburetors adapted to supply a superrichmixture of fuel and airto said secondary mixing chambers, a primary throttle controlling flowthrough said primary carburetors, a secondary throttle controlling theflow of air to said secondary mixing chambers, and provided with anorifice therein to admit a limited amount of air during the idling ofthe engine.

12. A charge forming device for internal combustion engines having incombination a plurality of secondary mixing chambers, a plurality ofprimary carburetors adapted to supply a super-rich mixture of fuel andair to said secondary mixing chambers, a primary throttle controllingthe flow through the primary carburetors and adapted to be held in aslightly open position during the idling of the engine, a secondarythrottle controlling the fiow of air to the secondary mixing chambers,means holding said throttle closed at idling, said secondary throttlehaving an orifice therein to admit a limited amount of air to thesecondary mixing chambers when said throttle is closed.

13. A charge forming device for internal combustion engines having aplurality of intake ports comprising a plurality of secondary mixingchambers supplying fuel mixture to said ports, a plurality of primarycarburetors supplying fuel mixture to said secondary mixing chambers,primary and secondary throttles controlling the primary carburetors andsecondary mixing chambers respectively, a fuel conduit having a singlefuel metering orifice for supplying all the fuel to said primarycarburetors and means operated by one of said throttles for regulatingthe flow of fuel through said-orifice. "14. A charge forming device forinternal combustion engines having a plurality of intake ports.comprising a plurality of secondary mixing chambers supplying fuelmixture to said ports, a plurality of primary carburetors supplying.fuel mixture to said secondary mixing chambers, primary and secondarythrottles controlling the primary carburetors and secondary mixingchambers respectively, a fuel conduit having a single fuel meteringorifice forsupplying all the fuel to said primary carburetors, and meansoperated by the primary throttle for regulating the flow of fuel throughsaid orifice.

' '15. A charge forming device for internal combustion engines having aplurality of intake ports comprising a plurality of secondary mixingchambers supplying fuel mixture to said ports, a plurality of primarycarburetors supplying fuel mixture to said secondary mixing chambers,primary and secondary throttles controlling the primary carburetors andsecondary mixing chambers respectively, a fuel conduit having a fuelmetering orifice for admitting fuel to said primary carburetors, andmeans operated by one of said throttles for variably regulating the flowof fuel through said orifice during the entire movement'of saidthrottle.

16. A charge forming device for internal combustion engines having aplurality of intake ports comprising a plurality of secondary mixingchambers supplying fuel mixture to said ports, a plurality of primarycarburetors supplying fuel mixture to said secondary mixing chambers,primary and secondary throttles controlling the primary carburetors andsecondary mixing chambers respectively, a fuel conduit having a fuelmetering orifice for admitting fuel to said primary carburetors, andmeans operated by said primary throttle for variably regulating the flowof fuel through said orifice during the entire movement of saidthrottle.

17. A charge forming device for internal combustion engines having aplurality of intake ports comprising a plurality of secondary mixingchambers supplying fuel mixture to said ports, a plurality of primarycarburetors supplying fuel mixture to said secondary mixing chambers,primary and secondary throttles controlling the primary carburetors andsecondary mixing chambers respectively, means for supplying fuel to saidprimary carburetors and means operated by the primary throttle fordetermining the entire amount of fuel supplied to the primarycarburetors during all operating conditions.

18. A charge forming device for internal combustion engines having aplurality of intake ports comprising a plurality of secondary mixingchambers supplying fuel mixture to said ports, a plurality of primarycarburetors supplying fuel mixture to said secondary mixing chambers,primary and secondary throttles controlling the primary carburetors andsecondary mixing chambers respectively, a fuel feeding orifice forsupplying fuel to said primary carburetors, a fuel valve controlling theflow of fuel therethrough and a cam operated by the primary throttlethroughout its movement for varying the supply of fuel in accordancewith the movement of the throttle.

FRED E. ASELTINE.

